Center-of-mass correction in the MIT bag model

The Peierls-Yoccoz method is used to treat the center-of-mass (c.m.) motion of hadrons in the MIT bag. The results are found to agree with those obtained in the intuitive procedure of Liu and Wong. The method of Donoghue and Johnson for making c.m. corrections is found to be incorrect. The pion decay constant $F_{\pi }$ is calculated from the now known c.m. motion of the pion in the bag. It turns out to depend strongly on the three-momentum of the pion.